Robb Mohr sat by his wife's hospital bed two weeks ago, trying to take it all in. His wife, Jolee Mohr, was breathing with the help of a ventilator in a Chicago intensive care unit -- her body bloated from internal bleeding, her liver failing -- and no one could figure out what was wrong with her.

Robb Mohr had his suspicions. Jolee, 36, had been feeling fine just a few weeks earlier, save for occasional stiffness from her arthritis. Her decline had begun the day after her right knee was injected with an experimental drug made of genetically engineered viruses. Doctors at the hospital shared his concern.

Jolee Mohr died from massive bleeding and organ failure July 24, leaving behind a 5-year-old daughter and a host of questions about why she was recruited into a gene therapy experiment whose chief goal was to test the safety of a novel arthritis treatment that had virtually no chance of helping her.

No one knows yet whether the treatment was to blame. Of the dozens of other volunteers who got the injections, only Mohr suffered anything more than short-lived side effects, said officials at Targeted Genetics Corp., the Seattle company that makes the product. The Food and Drug Administration and the company are investigating.

But a close look at the events leading to Mohr's death reveals failures in the safety net that is supposed to protect people from the risks of medical experimentation -- and in particular, the risks of gene therapy, which for 17 years has struggled in vain to live up to its optimistic name.

Breaches of clinical research standards and a federal oversight system that allowed key decisions to be made behind closed doors may have helped draw Mohr into an experiment that was not, her husband says, what she thought it was.

"It was presented to her like this is going to make her knee better," said Robb Mohr, an agronomist who lived with his wife of nine years in a modest vinyl-sided ranch home near Springfield, Ill. "It was supposed to be just a simple thing."

Company officials vigorously defend the study, saying they were upfront about risks, adhered to all regulations and were terribly saddened by the loss. "We're human," said H. Stewart Parker, Targeted Genetics' chief executive. "This is not just a patient. This is a person, and this is a horrible tragedy."

A two-sentence paragraph halfway through a 15-page consent document that Jolee Mohr signed warns of the possibility of "unknown side effects," including, "in rare circumstances, death."

Further in, after long descriptions of how the product may help, a single sentence states: "We do not expect you to receive any direct medical benefits from participation in this study."

Mohr was in an early-phase study, the prime goal of which was to see whether the treatment was safe, not to provide a therapeutic benefit. If the drug passed muster, other studies would determine whether it was an effective treatment.

Her rheumatologist, Robert Trapp, whose Springfield clinic got payments from Targeted Genetics for each subject he recruited, also defended the study. "The theory behind it seemed good, and the science seemed good," he said. "There's nothing I knew of that could have predicted this."